Most tunnel boring machines finish a job the boring way. Crews dig a shaft at the far end, crane the machine out, hose it off, and truck it to the next contract. The machine that cut Enid, Oklahoma’s new water intake never had that option, because the far end of its tunnel was the bottom of Kaw Lake. So it drove out through the lakebed, and a dive crew went down to collect it.<\/p>\n
That recovery happened back in 2022. The reason I’m dragging it back up now is that the system the tunnel feeds is finally finished. Enid held the ribbon-cutting for its new water treatment plant on August 21, 2026, the last major piece of a program that moves lake water down 70 miles of pipe to a city that’s been living off its aquifers. Every gallon Enid pulls from Kaw Lake enters through the steel tube that machine left behind.<\/p>\n
Enid’s spent decades pumping drinking water from well fields west of town, and between drought and growth, the city went looking for a second source. It settled on Kaw Lake, an Army Corps of Engineers reservoir roughly 70 pipeline miles to the east. The program built around it has four pieces: an intake at the lake, 70 miles of 36-inch raw water pipeline with booster stations, a new treatment plant, and upgrades to the distribution system. The EPA loan paperwork behind the program<\/a> lays out what the city wanted: enough water to cover projected growth, a 35 percent cut in average daily demand on the regional aquifers, and 7.5 miles of old cast iron pipe with lead-sealed joints pulled out of the ground. Vance Air Force Base and several neighboring water customers ride on the same system.<\/p>\n An intake’s just the opening where lake water comes in, but you can’t put an opening like that anywhere near the surface. It’s got to sit low, where the water stays through a dry year, and it’s got to be protected from silt, ice, and boat traffic. So crews sank a shaft about 100 feet deep beside the lake, sealed it against the water pressure, and pushed a boring machine sideways through solid rock until it broke through beneath the lakebed. Trenchless people call that a lake tap. I’d call it threading a needle you can’t see from a room you can’t let flood.<\/p>\n The machine was an Akkerman SL74P, a slurry microtunneling rig, which is a mouthful for what’s honestly a pretty simple idea. Nobody rides inside it. An operator runs the whole thing from a control container up top while a cutterhead grinds away at the rock face. A loop of pressurized slurry carries the cuttings back out, and that same pressure holds back the groundwater trying to force its way into the heading. Behind the machine, a hydraulic jacking frame down in the shaft shoves lengths of 72-inch steel casing forward, so the tunnel lines itself as it grows.<\/p>\n The frame on this job was rated for 800 tons of thrust, and it apparently needed the muscle. Akkerman’s project sheet<\/a> describes the ground as hard rock with a high hydrostatic water head, meaning the machine was grinding through rock while the lake above kept pressing water into every seam. The drive ran 510 feet from the shaft to the breakout point, per that sheet. I’ll admit the paper trail isn’t perfectly tidy here: a 2022 trade job log put the run at approximately 476 feet while the work was still being written up, so I’m going with the figure the machine’s manufacturer published afterward.<\/p>\n So how do you get the machine back?<\/p>\n You don’t dig it out, because the receiving pit is a lake. The SL74P was built for exactly this ending, with high-pressure seals and bulkheads that kept Kaw Lake from flooding back down the fresh tunnel once the cutterhead punched through. Garney, the contractor on the intake, sent its marine crew to lift the machine off the lake bottom, and the company’s photos of the recovery are frankly some of the strangest images municipal waterworks will ever produce: a tunnel boring machine on a crane line, coming up through open water. The tunneling itself was run by Super Excavators, a Wisconsin outfit that’s been microtunneling since 2001. And this exit isn’t unique, because a boring machine in California made a similar move<\/a> on another intake job we covered in July.<\/p>\n What’s left in the rock is a 6-foot-wide steel passage running from the lake down to the shaft, and as of this summer, there’s a whole water system hanging off it. Raw water gets pumped from the intake, rides 70 miles of 36-inch pipeline through booster stations, and lands at the new plant on Chestnut Avenue in Enid, built to blend lake water with the city’s existing well supply. If you live in Enid, the plan is that some of what comes out of your faucet starts life in a reservoir 70 miles away.<\/p>\n The treatment plant broke ground in November 2021 and spent June of this year in a 30-day shakedown, with crews testing equipment, treatment processes, and dosing against state and federal water quality standards. The completion ceremony came on August 21, and City Manager Jerald Gilbert didn’t undersell it, calling the program “the most complicated, complex, costly, challenging project in our city history,” per the Enid News & Eagle<\/a>. The city can pump an average of 10.5 million gallons a day from Kaw Lake, and there’s room in the design to grow that to 21 million a day later on.<\/p>\n None of it came cheap. Garver, the program’s lead designer, prices the full build-out at $475 million, and Enid voters approved a one-cent sales tax to repay the state water board loans behind it, with the city expecting to retire them in 2052. For a city of roughly 50,000 people, that’s a pretty serious bet on the next 50 years of water. It’s also part of a busy stretch for machines that eat rock for a living, right after a borer broke through under a Canadian mountain<\/a>.<\/p>\n The borer left through the lake years before anybody got to celebrate, and I can’t tell you where that particular machine ended up, because nobody publishes tour schedules for tunneling equipment. Enid got its moment anyway: the city marked the full Kaw Lake program complete on August 21, 2026, with 10.5 million gallons a day of new capacity and a 6-foot steel doorway at the bottom of a lake to feed it.<\/p>\n","protected":false},"excerpt":{"rendered":" Most tunnel boring machines finish a job the boring way. Crews dig a shaft at the far end, crane the … <\/p>\nAn 800-ton frame did the pushing<\/h2>\n
It came out the wet way<\/h2>\n
Enid finally got its ribbon-cutting<\/h2>\n